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authorDavid Howells <dhowells@redhat.com>2019-10-07 10:58:29 +0100
committerDavid Howells <dhowells@redhat.com>2019-10-07 11:05:05 +0100
commit9ebeddef58c41bd700419cdcece24cf64ce32276 (patch)
tree7e4fbd61beb570d2abca88a4e00276f9c8b3ebc4
parent48c9e0ec7cbbb7370448f859ccc8e3b7eb69e755 (diff)
rxrpc: rxrpc_peer needs to hold a ref on the rxrpc_local record
The rxrpc_peer record needs to hold a reference on the rxrpc_local record it points as the peer is used as a base to access information in the rxrpc_local record. This can cause problems in __rxrpc_put_peer(), where we need the network namespace pointer, and in rxrpc_send_keepalive(), where we need to access the UDP socket, leading to symptoms like: BUG: KASAN: use-after-free in __rxrpc_put_peer net/rxrpc/peer_object.c:411 [inline] BUG: KASAN: use-after-free in rxrpc_put_peer+0x685/0x6a0 net/rxrpc/peer_object.c:435 Read of size 8 at addr ffff888097ec0058 by task syz-executor823/24216 Fix this by taking a ref on the local record for the peer record. Fixes: ace45bec6d77 ("rxrpc: Fix firewall route keepalive") Fixes: 2baec2c3f854 ("rxrpc: Support network namespacing") Reported-by: syzbot+b9be979c55f2bea8ed30@syzkaller.appspotmail.com Signed-off-by: David Howells <dhowells@redhat.com>
-rw-r--r--net/rxrpc/peer_object.c5
1 files changed, 3 insertions, 2 deletions
diff --git a/net/rxrpc/peer_object.c b/net/rxrpc/peer_object.c
index b700b7ecaa3d..64830d8c1fdb 100644
--- a/net/rxrpc/peer_object.c
+++ b/net/rxrpc/peer_object.c
@@ -216,7 +216,7 @@ struct rxrpc_peer *rxrpc_alloc_peer(struct rxrpc_local *local, gfp_t gfp)
peer = kzalloc(sizeof(struct rxrpc_peer), gfp);
if (peer) {
atomic_set(&peer->usage, 1);
- peer->local = local;
+ peer->local = rxrpc_get_local(local);
INIT_HLIST_HEAD(&peer->error_targets);
peer->service_conns = RB_ROOT;
seqlock_init(&peer->service_conn_lock);
@@ -307,7 +307,6 @@ void rxrpc_new_incoming_peer(struct rxrpc_sock *rx, struct rxrpc_local *local,
unsigned long hash_key;
hash_key = rxrpc_peer_hash_key(local, &peer->srx);
- peer->local = local;
rxrpc_init_peer(rx, peer, hash_key);
spin_lock(&rxnet->peer_hash_lock);
@@ -417,6 +416,7 @@ static void __rxrpc_put_peer(struct rxrpc_peer *peer)
list_del_init(&peer->keepalive_link);
spin_unlock_bh(&rxnet->peer_hash_lock);
+ rxrpc_put_local(peer->local);
kfree_rcu(peer, rcu);
}
@@ -453,6 +453,7 @@ void rxrpc_put_peer_locked(struct rxrpc_peer *peer)
if (n == 0) {
hash_del_rcu(&peer->hash_link);
list_del_init(&peer->keepalive_link);
+ rxrpc_put_local(peer->local);
kfree_rcu(peer, rcu);
}
}